[HELP !]

I recently received a call from my lender that said I had qualified for their loan modification. I was told there was not any fee and that it would knock 4 years off my loan and lower my payments by over 150 dollars a month. I have perfect credit, never missed a payment, and didn't inquire about a lower rate. So am I missing something here ? This almost seems to good to be true. I currently have a 30 year fixed @ I think a 5% rate. I am 8 years into this loan. Any help here would be much appreciated. . . .